Clipping Warnings In Photo Persona

[Lisbon]

CLIPPING WARNINGS IN PHOTO PERSONA USING PROCEDURAL TEXTURES

Develop persona allows you to see clipped areas. I have created three procedural texturas to reveal this areas in photo persona.

First procedural texture: Clipping Shadows/Highlights
Here is an example where shadows and highlights are clipped.

Just like develope persona i used red and blue to show the warnings. Red for highlights and blue for shadows.

Second procedural texture: Clipping RGB
This procedural texture shows warnings for each channel when a pixel reaches 0 or 255.
Each channel has its own warning colour. Single colour per channel.

In this example i went too far setting the black level on the green channel.

Usually you will only see warnings in red, green or blue but it is also possible to see cyan, magenta or yellow.
Lets take for example a yellow warning. If you add red and green you get yellow so a yellow warning refers to the red and green channel.
Cyan = Green + Blue
Magenta = Red + Blue

Third procedural texture: Clipping RGB - Black background
Sometimes its hard to see the warnings because they look they are blended whith the image.
This procedural makes the image completly black while the warnings remain in colour.
It is like when you select the levels adjustment and hold down the alt key but in this case the warnings are visible while editing each channel.

If you found this usefull you can download the file at the end or paste this formulas.

First procedural texture: Clipping Shadows/Highlights
var trigger=floor(0.5+abs(average(R,G,B)-0.5)); trigger*R + (1-trigger)*R
var trigger=floor(0.5+abs(average(R,G,B)-0.5)); (1-trigger)*G
var trigger=floor(0.5+abs(average(R,G,B)-0.5)); trigger*(1-B) + (1-trigger)*B

Second procedural texture: Clipping RGB
var rgb=floor(max(R,G,B,1-min(R,G,B))); var red=floor(0.5+abs(R-0.5)); rgb*red + (1-rgb)*R
var rgb=floor(max(R,G,B,1-min(R,G,B))); var gre=floor(0.5+abs(G-0.5)); rgb*gre + (1-rgb)*G
var rgb=floor(max(R,G,B,1-min(R,G,B))); var blu=floor(0.5+abs(B-0.5)); rgb*blu + (1-rgb)*B

Third procedural texture: Clipping RGB - Black background
var rgb=floor(max(R,G,B,1-min(R,G,B))); var red=floor(0.5+abs(R-0.5)); rgb*red
var rgb=floor(max(R,G,B,1-min(R,G,B))); var gre=floor(0.5+abs(G-0.5)); rgb*gre
var rgb=floor(max(R,G,B,1-min(R,G,B))); var blu=floor(0.5+abs(B-0.5)); rgb*blu

clipping_warnings.afphoto

[Lucio]

Thank you for Sharing.

Very useful workaround for an AP lack I hope will be soon solved.

[BCrompton]

Thank you, Lisbon, for your excellent solutions. However, I have hit a problem with the Clipping Shadows/Highlights texture.

I'm using Affinity Photo 2.5.5 and editing from a RAW file (NEF) with the sRGB IEC61966-2.1 profile applied. After hitting Develop and saving as an .afphoto file, I add the first procedural texture layer. When I add a Levels adjustment and raise the Black Level, the blue shadow warnings appear immediately. However, I can't get the red highlight warnings to show no matter how far I lower the White Level. Here's why ...

When the Clipping Shadows/Highlights texture is disabled and I use the colour picker to sample a blown out area, the RGB reading is R: 255 G: 255 B: 255, as you'd expect. When I enable it and sample the same area, however, the reading changes to R: 255 G: 254 B: 255. In other words, I'm not seeing any red clipping warnings because I can't make any pixel anywhere in the photo reach pure white. That's because the Green Channel maxes out at 254.

This happens when I'm editing in .afphoto. When I export to a 16-bit TIFF file and edit that, the same thing happens, but the Red channel also maxes out at 254. When I export to a JPEG, all three channels reach 255 and the red highlights appear. The other two textures work perfectly.

I tried applying the ROMM, Adobe RGB and Nikon RGB colour profiles in the Develop persona, but get the same results. It has me baffled. Are you able to help, please?

Brian 

 

[BCrompton]

Solved (I think). I had the RAW Output Format set to 16-bit in the Develop Assistant. When I switched to 32-bit HDR, the pure whites were retained in the Photo persona and the red clipping warnings appeared. 

I don't know enough about colour gamuts to understand why pure white in 16-bit should be any different to 32-bit when converted to sRGB. The maximum value is still 255 in each channel, so why the green channel value dips by 1 (along with the red channel in TIFF), I don't know.

Still, your superb textures are now working and doing a great job!

Thank you.

Brian

 

[judepereira]

Hi

Much appreciate if you could tell me how I add these clipping warnings to my Affinity Photo

 

Thanks 

Jude